1. Technical Field
This invention relates, generally, to data processing systems and, in particular, this invention relates to the placement of circuit board modules in data processing systems. More particularly still, this invention relates to a modular holder for IC packs that is easily replaceable.
2. Description of the Related Art
Current data processing systems require package systems that are designed to be compact and easy to service and upgrade at the end user site. The compact designs are necessary because they are easily utilized in office environments where the availability of space is limited or special environmental conditions are required by the data processing systems, such as, for example, mainframe computers and mid-range computers. In addition, data processing systems typically come with a number of options, and the end user may wish to add or remove options at any time after initial installation. It is desirable that the field service representative or end user be able to make these changes in the minimum time possible without the need for special tools.
A common method of achieving the goals of compact design and ease of field service and field upgrades is to employ a modular circuit board design. A common type of modular design provides for a main circuit board, which may be referred to as the "mother board". The mother board usually contains the basic computer circuitry essential for operation of the data processing system. One or more additional circuit boards are used to provide optional or enhanced functions. The circuit boards containing circuitry necessary to accomplish the optional functions can be referred to as "daughter boards". Daughter boards can be electrically connected to the mother board over multi-pin bus connectors.
Some modular designs also are limited in holding but a single logic card per modular cover set. Accordingly, it was not possible to have more than one logic card per modular package. Additionally, some data processing systems did not provide for a modular systems to be added or removed from the overall system. This prevented field upgrade or replacement of the logic cards.
In data processing systems today, card real estate is still at a premium; accordingly, additional expansion cards are provided where components that cannot fit on the mother board are then added. Recently, modular designs have been developed that allow for placement of more than one logic card in a modular unit. Field replacement and upgrading is still cumbersome in these designs since they do not provide for the replacement of a single card that may have failed or need upgrading, but rather require the replacement of the entire modular unit. This would require the group supporting the data processing system to store every possible combination of cards in a particular modular package.
Accordingly, what is needed is a modular package that allows multiple internal logic cards and that is easily upgradable or replaceable either through replacement of the entire modular package or by changing of any one of the internal logic cards found within the modular package. Additionally, what is also needed is a modular package that not only provides for the attachment of multiple modular cards, but also the attachment of incompatible cards, such as single in-line memory modules (SIMM), that do not fit in a standard expansion slot found in traditional data processing systems.